public static void swap(int x,int y){
    int t= x;
    x = y;
    y = t;
}
public static void swap (ref int x,int y){
    int t = x;
    x = y;
    y = t;
}
public unsafe static void swap(int* x,int* y){
    int t = *x;
    *x = *y;
    *y = t;
}
public static void change (int[] arr){
    for(int i = 0;i<arr.Length;i++){
        arr[i] = i;
    }
}
public static int TesetOut(out char i){
    i = 'b';
    return -1;
}